Answer: The Rema (OC 473:6) writes that one should read the haggada in a language that everyone understands or explain the main points well. The Mishna Berura (473:64) points out that this is to ensure that one fulfils the mitzva of ‘vehigadeta levincha, teach it to your children’ (Shemos 13:8).
R’ Ephraim Greenblatt (Rivevos Ephraim 1:302:2; 3:314) writes that one hasn’t fulfilled their mitzva if they don’t understand what they are reading (See Minchas Chinuch 21:11). Thus, just reading the words in Hebrew wouldn’t suffice.
The Shulchan Aruch Harav (OC 473:24) and Chassam Sofer (OC:15) write that ideally one person should read the haggada while others fulfil their obligation by listening, shomea keoneh. According to Maaseh Rav (291), this was the practice of the Vilna Gaon, too. Likewise, R’ Shlomo Zalman Auerbach (Halichos Shlomo, Pesach 9:31) and R’ Ephraim Greenblatt (ibid. 1:369; 5:323; 8:202:1) write that one can fulfil their obligation by listening to other adults read the haggada.
In conclusion, it is preferable to listen to others read the haggada in a language that you understand, rather than say all the words like davening.